1. Field of the Invention
The present invention relates to typewriters in general and, in particular, to typewriters having a capability for storing a plurality of operator supplied phrases for selective playback in response to an operator triggered command signal.
2. Discussion Relative to the Art
It is known to record codes produced by the keyboard apparatus of a typewriter for subsequent retrieval to drive a printing unit. Such capability has been provided, for example, using magnetic or paper tape storage having tracks or positions which may be individually accessed. U.S. Pat. No. 2,717,686 describes a typewriter apparatus that can be preprogrammed to print multiple character combinations in response to depression of respective keys. The memory for such apparatus, however, is not easily loaded by the operator.
With the advent of low cost semiconductor memories it has become feasable to provide for facile storage and recall of commonly used phrases. To justify the expense of implementation, however, the memory dedicated to phase storage must be used in a highly efficient manner and phrase-storage, -recall, and -replacement procedures must be convenient for the operator. Also it would be desirable for implementations using volatile storage to minimize susceptability to loss of the stored phrase information in the event of a temporary loss of power or of an undervoltage condition.